ADVOCATES:John N. Koester, Jr. - for the petitionerNicole A. Saharsky - Assistant to the Solicitor General, Department of Justice, for the United States as amicus curiae, supporting the petitionerSteven R. Shapiro - for the respondent

Facts of the case

On October 3, 2010, Missouri state police officer Mark Winder saw Tyler McNeely driving above the speed limit. When Winder followed McNeely to pull him over, he saw McNeely cross the center line three times. Upon making contact with McNeely, Wilder observed that his eyes were red and glassy, and that his breath smelled like alcohol. McNeely performed poorly on four field sobriety tests and refused to submit to a portable breath test. Wilder arrested McNeely for driving while intoxicated and transported him to a hospital to obtain a blood sample. Wilder read McNeely the Missouri Implied Consent statement, and McNeely still refused to submit the sample. Wilder ordered the sample taken anyway, and the blood test revealed McNeely's blood alcohol level was far above the legal limit.

The state charged McNeely with driving while intoxicated, and McNeely moved to suppress the evidence of the blood sample because it was obtained without a warrant. The trial court granted the defendant's motion. The state appealed and argued that the risk of McNeely's blood alcohol level decreasing over time represented an exigent circumstance requiring a blood draw. The Missouri Court of Appeals held that the trial court erred, but that the case represented a departure from current case law; it transferred the case to the Missouri Supreme Court. The Supreme Court of Missouri affirmed the trial court's decision.

Question

Does the Fourth Amendment prevent the taking of a warrantless blood sample under exigent circumstances?

John G. Roberts, Jr.:

Justice Sotomayor has the opinion of the Court today in case 11-1425, Missouri versus McNeely.

Sonia Sotomayor:

This is a case about when the police must obtain a warrant before conducting a non-consensual blood test of the drunk-driving suspect.

Respondent Tyler McNeely was pulled over the middle of the night after a highway patrol officer observed him driving erratically.

McNeely also exhibited other signs of intoxication and he admitted that he have had a couple of beers at a bar.

After McNeely performed poorly on several sobriety tests, the officer asked him to take a breathalyzer test.

He declined.

The officer took McNeely without his consent to a nearby hospital for a blood test instead.

The subsequent testing revealed that McNeely's blood alcohol concentration or BAC was well above the legal limit.

McNeely was charged with driving while intoxicated. He moved to suppress the blood test arguing that drawing his blood without a search warrant violated his rights under the Fourth Amendment.

A trial court agreed.

The court concluded that it would have been practical under the circumstances for the officer to obtain a warrant and that there was no evidence, the officer faced an emergency.

The State appealed arguing that the loss of evidence that results from the body's natural processing of alcohol is on its own, a sufficient basis for acting without a warrant.

After an intermediate court transferred the case, the Missouri Supreme Court affirmed.

The Missouri Supreme Court stated that the permissibility of a warrantless blood draw should be through -- determined based on the totality of the circumstances.

The Court held that the fact that alcohol is naturally metabolized does not create a per se emergency that allows police officers to conduct the blood draw without a warrant in every case.

And the Court concluded that in McNeely's case, there were no circumstances or special factors that made a warrantless blood test reasonable.

We granted certiorari to resolve a split in authority on the question whether the natural dissipation of BAC evidence constitutes an inherent emergency that justifies warrantless blood draws in all drunk-driving investigations.

We now affirm.

Our cases have recognized that before the police may conduct to search of a person, they must generally have a warrant.

That principle applies to the search here which involved the physical needle intrusion beneath McNeely's skin to recover evidence of a crime requiring law enforcement officers to obtain authorization from a neutral magistrate judge before invading a person's body in search of evidence helps protect people's deep rooted expectations of privacy and the integrity of their bodies.

One well-established exception to the warrant requirement, this is so called exigent circumstances.

We have applied that exception in a variety of contexts including as is relevant here when the police need to act to prevent the evident destruction of evidence.

In evaluating whether law enforcement officers face exigent circumstances, we have consistently looked to the totality of the circumstances.

This is the approach we applied in Schmerber versus California where we upheld the warrantless blood draw based on the circumstances presented and it is an approach we adhere to today.

The State of Missouri supported by several amici including the United States contend that exigent circumstances always exists in drunk-driving cases because the human body naturally breaks down alcohol and as a result, BAC evidence is constantly being lost.

We reject this proposed categorical rule as overly broad.

While it is sometimes reasonable for police officers to conduct warrantless blood test when officers can obtain a warrant without undermining the search, the Fourth Amendment requires that they do so.

For reasons, we explained in greater detail in our opinion.

We conclude that it is sometimes practical for police officers to obtain a warrant before conducting a blood draw.